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DBNTALOR OTHER'GHAIR. n No. 882,478 j l Patntedwmay 8, 1888;

N. PETERS, PMlwLihngmplxnr, Wnhingiun. CV

lUNITEDY STATES PATENT OFFICE. j.

HENRY n. JUsrr, E PHILADELPHIA, PENNSYLVANIA.

DENTAL 0R QTHER CHAIR.

SPECFICTION forming part of Letters Patent No. 382,473, dated May 8, 1888.

Application tiled December 12, 1887. Serial No. 257.638. (No model.)

To all whom it may concern):

Be it known that I, HENRY D. JUsTI, a citizen of the United States, residing in the city and county of Philadelphia, State of Pennsylvania, have invented a new and useful Improvenient inv Dental or other Chairs, which improvement is fully set yforth in the following specication and accompanying drawings.

My invention consists of means for conveniently adjusting the seat and back of a dental or other chair, as will be hereinafter fully set forth.

Figure 1 represents a sideelevation of a portion ot' a chair embodying .my invention. Fig. 2 represents a top or plan view thereof. Fig. 3 represents a horizontal section thereof on line m as, Fig. 1,'on an enlarged scale. Fig. 4 represents a vertical section thereof on line y y, Fig. 3.

Similar letters of reference indicate corresponding parts in the several figures..

Referring to the drawings, A represents the standard of a dental or other chair. To the top of said standard is secured'a shelf, B, toV

which is pi voted theseat C ofthe chair, whereby said seat may be readily tilted as desired.

D represents a nut, from whose sides project the journals E, the latter being mounted on the front end of the shelf B. Fitted within the nut D is a screw-shaft, F, to whose upper end is keyed or otherwise rmly secured a spur-wheel, G, which is located within a box, H, said box having projecting from its sides the journals J, which are mounted in the ears K, secured to the inner face of the frame of the seat C, it being noticed that the upper end of the screw-shaft F is mounted in the boXH, as most clearly shown in Fig. 4.

Projecting rearwardly from the box H is a tubular guide, L, within which is fitted a tooth or dog, M, whose point engages with either of the teeth of the wheel G and is held in contactV with the same by the action of the spring N, which is located within the guide L and bears against said dog. Y

On the side of the guide L is an ear,]?,which forms a bearing for the lever Q, one end of which passes through the side of the guide L and engages with the dog M, the opposite end of said lever being accessible at the side of the chair. A

The operation is as -follows: The lever Q is Patent, isemoved so as to withdraw the dog M from engagement with the wheel G, andthe seat may now be tilted up or down as required.' When the screwshaft F'is raised with the front end of the seat, it rotates in the nut D as it is drawn through said nut. The same result `is accomplished when said end of the seat is lowered, the shaft in either case controlling the motion of the seat, so that abrptness of the -same'is prevented and the occupant of thev seat cannot be violently thrown backward or forward. When adjustment of the seat is obtained, the lever Q is let go, whereby the/dog M engages with the adjacent tooth of thewheel G, thus preventing return of the latter and of the screw-shaft, whereby further ascent or descent of the seat, as the case may be, is prevented, it being evident that the dog M is adapted to engage with either of the teeth of the wheel G, so that the seat may be adjusted with nicety relatively to the number of teeth on said wheel G. Owing to 'the journals E J of the nut D and box H, respectively, said parts D H turn on their bearings as theseat is tilted, thus preventing binding of or strain on the screw-shaft F. The back C' is pivoted to the frame of the seat 0,.' and its angle may be changed as desired, said back and frame having connectedk to 'them the box H' and nut D', with the journals J E', the ears K', screwshaft 'F, lwheel G',"guide L', dog M', spring N', ear P', and lever Q', said .parts being similar to those employed for adjusting the seat C; but, as is evident, the screw-shaft occupies somewhat of a horizontal position and the other parts are harmoniously arranged in-relation thereto, so that the screw-shaft F may be rotated as the'back is moved on its pivot, its wheel G being adapted to be vlocked and unlocked bythe action of the dog M' similar to the dog M of the wheel G.

p I am aware that it is not new to construct a dental chair with a tilting seat having an adjustment therefor consisting of a screw-shaft connected with the part to which the seat-'frame is pivoted and working in a swinging nut having its j ournal-bearings rigidly attached' to the seat-frame, and therefore do not claim the same.

Having thus described my invention, whatllICO claim as new, and desire to secure by Letters 1. A chair havingaframepivoted to asupjj port, a. nut having journal-bearings in said support, ears secured to the frame, a box having journal-bearings in said ears, a screwshaft Working in said-nut, a spur or toothed wheel secured on said shaft so as to rotate therewith and in said box, a tubular guide leading into said box, a dog in said guide, and a pivoted lever engaging said dog, said parts being combined substantially as and for the purpose set forth.

2. A chair having a. standard with shelf thereon, a frame pivoted to saidstandard, the nut D, having journals E, with bearings in HENRY D. JUSTI.

Witnesses:

GEO. L. SMALL, JOHN A. WIEDERSHEIM. 

